It'll not be the most fuel efficient though compared to modern unit and you certainly won't get that length of time out of anything out today thats for sure.
Another reason not to change it. What's the fuel efficiency going to save me? £5 a month probably, against an install cost in the thousands. House is being sold on anyway so I've got a new to me boiler to worry about soon.
I mean probs more than that but its difficult to work that one out as much because gas prices are ridiculous now. They say the bigger the house though the more you'll save.
You're boiler i dont know what it is was maybe 60 percent efficient new but 25 ish years on might be 40 percent.
It'll not be the most fuel efficient though compared to modern unit and you certainly won't get that length of time out of anything out today thats for sure.